Telephone system



March 16, 1954 E c. E. LOMAX 2,672,513

TELEPHONE SYSTEM Filed July 29, 1950 4 Sheets-Sheet l 0: In" '1?! z 1% El 1 J I l l FIG I REG sue 2 2s 24 I00 28 29 2 26 23, 27 so IN V EN TOR. CLARENCE E. LOMAX ATTORNEY c. E. LQMAX TELEPHONE SYSTEM March 16, 1954 4 Sheets-Sheet 2 Filed July 29, 1950 IN V EN TOR. C LARENCE E. LOMAX ATTORNEY March 16, 1954 c. E. LOMAX TELEPHONE SYSTEM 4 Sheets -Sheet 3 Filed July 29, 1950 IN VEN TOR. CLARENCE E. LOMAX wmmy O n m. 4 mmNN mon 4+ SON ATTORNEY March 16, 1954 c. E. LOMAX 2,672,513

TELEPHONE SYSTEM Filed July 29, 1950 4 Sheets-Sheet 4 m m n fi r. m E lav mt m n n u u Emmi n 62 u u n n m n u u m E u Hmbmv omw u n u zww wmv INVENTOR CLARENCE E. LOMAX ATTORNE? Patented Mar. 16, 1954 UNI-TE D STATES PATENT OFF ICE TEIIEPHONE SYSTEM Clarence Eoiiiax; Chicago; 111.; assignor to Au tomatic Electric Laboratories, Inc., Chicago.

Ill .a corporation ofiDelaware Application Ju1y"29,.1950,. Serial N6. 176,755

9 Glaima invention relates in general is telephone" systems" and more particularly to an automatic telephen'e' system serving" both regular and pay stations; and still more particularly, it relates 156" an automatic telephone payst'ation system Whereln coin actuation is; value discriminatory.

It is the main objectof the invention toprov-ide an automatic t'elep'honesystem wherein the circuit arrangement is such that a-call from a paystation'can be made 'only when a coin of at least a predetermmed venue is deposited.

Another object of the invention is to provide means whereby a c'o'in'of lesser'value than said predetermined tame when used in' attemptto jects; a: feature of the" invention resides in the" means for returning'a coin oi-le'ss-tha'ri the proper vamearter'the first'digit of the deemed number i's dialled.

Anbtlier feature of the invention resides in the sending of an identifying" signal afterthe" first d'igit'has been dialledwhere' the proper value coin been deposited.

An6filel feature Of the system fesids'ifl Vi'Sifih of a paystation'control' t'llll'lk serving both ga stations andregular stations; but'arrans'ed'to be bypassed by'calls from regular lines.

Anotherfeatui' of the system resides in a. new

aiid'iinproved'selector which gives station identi fic'ation as to a calling line to a" toll operator by twain-earls, visual'auu audio. H H And still anothef' feature o'f theinventi'on're sides in the automatic refunding" means when the toll operatori's' reached. I

These'and otherobje'ct's' and features" will be more particularlydescribed in the-following spec'- ification and appended Claims taken conjunc' tion with the'acco'm'panying drawings in which:

Figure 1 shows "ap'a'yst'ation circuit B in detail, a regular subscriber substation A schematically and block diagrams of their respective line cir-' tili ilis afid a faurwiper finder servine'them.

Figure 2 shew-s in" detain the circuitarranee ment' of a paystatioh' control trunk servingv the substation equipment in Figure 1.

Figure 3' shows a detailed selector circuit. Figure 4 showsa detailed combine'd line and recording (CLR) trunk as well as schematically showing a connectonlinecircuit-and regular subscriber substation C.

Referring now to the drawings, a general resume of the invention follows.

The automatic telephone p'aystation system-hi the instant invention comprisesfour mam-- elements, a coin controlled substation; apaystati'on trunk, a selector and a -combi'ned unease recording trunk, the latter hereinafter to be referred toas a CLR. trunk. conventional line circuit and a four wiper finder are shown schematically and beyondtheir normal functions; do not have any special significance'in the'instant application.v

The pay-substation circuit is similar to that shown in" U. S. Patent 2,214,259, issued to Pye; September 10, I940 withmodificationsadapting it to use as a payst'ation, namely'coin actuated cont'acts, a coin magnet and an internal coin transmitter; and also, for the purposes of this inven tion to be brought'out in detail hereinafter,v the dial employed is somewhat similar to that shown in U. s. Patent 2;366-,647,lissued to ostli-ne, Janu ary 2, 1945'.

The coin actuated contacts differ from that found in a conventional paystation in that one" is-placedto be actuated by nickels while another is ositioned to be acte'd upo'n by dimes and quar terse Mechanical latches for these contacts or triggers are provided which lock the contact in operated position after a coin has acted upon it. The coin disposal magnets are so arranged as to release either or both latches whenever coin disposal potential energizes the magnets. One of the purposes of this arrangement is to require an increased" initial deposit to actuate a call-while providing means for refunding coins of avalue lesser than that required for actuation. A dis-- charge device in the form of a neontube'has been placed in the coin disposalmagnets energizing paystations and regular subscriber's substation equipment. e

The finder employed is also conventional, and has four wipers. The fourth wiper discerns whether a call originates from a paystation or a regular subscriber. To accomplish this, the bank contact for the fourth wiper is grounded for paystations and open for regular subscribers. A four wiper finder similar to the one shown schematically herein is described in an application of Lomax, Serial No. 702,846, filed October 11, 1946, not yet issued.

The paystation trunk in Figure 2 is so arranged to by-pass calls from regular subscribers but operates responsive to a paystation initiated call. Other features of this trunk circuit will be detailed hereinafter.

Figure 3 shows an improved selector circuit which permits better line identification between paystation calls and regular subscriber calls, as well as increases the efficiency of the finders, selectors, CLR trunks and toll operators.

Figure 4 shows a new CLR trunk to operate with the above switch train and equipment. It is so constructed to distinguish toll calls of regular lines from paystations and gives coin service only to the latter.

These and other features will be: detailed hereinafter.

Having briefly described the invention, a detailed description follows. In this respect, several calls will be described from and to the various types of equipment served and in this manner, it is believed, a more complete and detailed description will be accomplished.

paystation local call, less than a dime deposited Assume that it is desired to make a local call from paystation B to another phone served by the same exchange, such as C. When the hookswitch 1 is raised, a loop circuit is closed to the line relay, not shown, in the line circuit over line L, pulsing contact i of the dial, hookswitch contact 2, induction coil winding l0, transmitter I3, tone transmitter l5 and tone transmitter resistance l6, and over the +L line. The line relay upon energizing over this loop starts the finder in well known manner and as soon as the finder finds the calling line, dial tone from the selector is placed on the +L line from dial tone generator D. T. thru contact 3', lower windings of relays 320 and 3m and contact 322A. The calling party hearing this tone knows that a finderselector link is in readiness for him and he may now deposit his coin.

As previously stated in the general description,

the mechanism of the paystation is so arranged as to have nickels operate spring 22 only, while dimes and quarters operate spring 26 only. All coins are retained in the hopper in well known manner until disposed of, either refunded or collected. Either coin spring 22 or 26 will connect the coin magnet ma between ground and the line so that disposal may be had. However, as a discharge device in the form of a gas filled tube 30 is in series with the coin magnet I95}, the circuits to magnet 108 are not actually closed until booster potential is applied to the line, firing the tube and energizing the magnet. The purpose for this tube is to improve transmission by eliminating ground leakage thru the magnet and it improves the pulsing over the line for the same reasons.

It will here be remembered that one of the objects of this invention is to enforce the deposit of an increased amount of money before a call may be made. The arrangement shown requires that at least a dime or a quarter be deposited to initiate a call. The deposit of a nickel or no coin at all will result in no call being possible. However, the arrangement is such that a nickel so deposited is refunded. In this conneciton, it is to be noted, that the central ofiice equipment is so arranged that the calling party must dial one digit before it is known whether the call will be permitted to go through and before the undervalue coin is refunded.

Assume further that the party in this call thru inadvertence or even bent on fraud has only deposited a nickel upon hearing dial tone, or fails to deposit any coin at all.

As the calling party is at a paystation, the EC bank contact of the finder belonging to the paystation is permanently grounded. This ground over the lead EC thru winding of start relay 210 to battery energizes relay 210 of the paystation trunk circuit. In operating, relay 2w opens contacts 2', 272 and 215 thereby removing the shunts from relays 266 and 2 i ii respectively. With their shunts removed, current flows thru both windings of shunt field relay 2l0 and differential relay 250. These circuits are traced from Dial Tone (D. T.) ground thru contact 3', lower windings of relays 32B and 3H contact 392A, conductor 295, contact 292, lower winding of differential relay 28G, contact 248, right-hand winding of shunt field relay 2m, over the +L conductor, thru the substation loop hereinbefore described, back over L conductor, contact 246, upper winding of relay 260, contact 29!, conductor 294, contact 301A, upper windings of relays Slil and 320 to battery; and from ground on the 0 lead of the finder thru contact 242, contact 214 closed by operation of relay 218 and thru the left-hand polarizing winding of shunt field relay 2!!! to battery. Altho current flows thru the circuits just described, neither relay 2H! nor 2% operate at this time due to their directional windings. Relay 218 in closing contact 214 also causes relay 238 to energize, the circuit therefor is traced from ground on the C lead of the finder thru contacts 242 and 2M, winding of relay 238 to battery. Relay 230 in operating closes contact 233 causing relay 24!! to energize from ground thereon. Relay 24D closes contact 241 and opens 242 placing ground therethru forward on the finder C lead to hold the finder busy against other calls.

In case the calling party deposited only a nickel, spring 22 is operated and looked under latch 24 which connects the coin magnet I00 thru the ground thereon to the line, but since the gas filled tube 30 is in series therewith, there is no operating ground on the L line to unbalance and operate differential relay 260. If no coin has been deposited the same is true except that the coin magnet I00 is not connected thru ground to the L line as neither spring 22 or 26 would be operated. At this point, the calling party hearing dial tone begins to dial the first digit of his number. lhe dial in returning, pulses line relay 320 in the selector over the circuit already traced for causing current to flow thru relays 260 and 210. In closing contact 32L the initial operation of relay 320 operates release relay 338 from ground thru contact 398, 32! winding of relay 330 to battery. Release relay 330 being sleeved for slow release holds operated during the pulsing. Relay 330 closes contact 33! placing ground thereon thru contact 35L Verti cal'off Normal (VON) Contact 316 and upper winding oi. relay 360 to. battery. Relay 30.0. onerates and closes a parallel circuit to its lower winding and vertical magnet 3.1.0 at contact 302. The first digit dialled pulses now alternately open and. close pulsing contact 322 stepping the V6101... cal magnet 310 of the selector iromv ground. thru contacts 309, 322, 334, 332, vertical magnet wind,- ing to battery. The selector therefore steps. V813? tically to the. selected level.

It may be seen that after the first verticalstep the Vertical Off Normal Springs operate and thereby open the original. energizing circuit for relay 360. During the remaining vertical pulsing period relay 36.0 is held operated. through its lower winding. Shortly after the vertical stepping, relay 300 restores. as its. circuit is opened at contact 334. and thus closes the circuit to the rotary stepping magnet at contact 36!. The so lector then seizes an idle trunk marked with batfiery by rotary stepping in well known manner; the rotary steppin circuit traced from ground thru: closed contacts 3 33, 34!, 306, 36l, cam contact 313, now closed VON contact 311, rotary interrupter contact 39!, rotary magnet 390 to bat tery. This stepping continues self interrupted until the C wiper encounters a battery marked idle trunk bank contact, which battery operates rotary stop relay 340 from said battery thru resistance 435, contacts 432, 463, conductor H2, contact 352, Winding of Rotary Stop relay 333, contact 332 to ground. Stop relay sec in operating opens the rotary stepping circuit at contact 34!. An idle trunk having. been seized on the selected level, switching relay 300 operates from ground thru contact 333 over a circuit therethru. thru winding of relay 300. and over the remainder of the rotary stepping circuit to battery on the rotary magnet. The current is insufiicien-t to onerate the rotary magnet inv series with relay 300 altho sufiicient to energize the latter. Switching relay 300 closes contact 303 energizing relay 290;- the circuit is traced from ground on the lead thru contacts 303, 273, 284, winding of reject cycle relay 290 to battery. Reject relay 230 operating opens the line circuit loop at contacts 29! and. 292 allowing the selector switch to release.

Relay 320 therefore restores and opens the circuit to the. release relay 330 at contacts 321. After an interval, slow to release relay 330' restores and prepares a circuit to release mag net 380 at contact 335. Relay 830 also, in restoring, opens the energizing circuit to relay 340 at contact 332 causing relay 340 to restore. Re lay 330 also, in restoring and opening contact 333, opens the energizing circuit to relay 300, causing it to restore. Relay 300, in restoring and closing contact 309, causes the release mag net 380 to operate over the following circuit: ground, contacts 303, 322, 335, 315, release magnet 380 to battery. The selector switch then returns to normal in a well known manner. When relay 330 falls back, opening contact 33!, relays 230 and 290 also release. Relay 290 is slugged so that it is slower to release than relay 230. While 290 is still holding up on its residual energy, relay 230 in releasing closes contact 252. As relay 240 is also slow to release, contact 234 momentarily remains closed so that disposal relay 245 operates; the circuit is traced from ground thru contacts 232. 244, winding of relay 245 to battery. Relay 245 in operating closes contacts 241' and 249 which applies -110 volt reiund potential thru contact. 241' to the -h line. which will fire the neon tube 30 and. energize. the disposal magnets I00 to. ground on inched spr ng 221s a nickel has been. deposited. The negative booster potential tips the polarized coin. dis posal magnets to refund position in well. known manner and the nickel, if deposited, is refunded. In operating, magnet I00 releases latch. 24.. opening contact 22'. If no coin had been deposited, no refund is necessary nor can it be made for lack of ground thru either coin spring.

After a slight delay, slow to release relay 240 falls back opening ground contact 242 which releases the finder. It also opens contact 244 releasing disposal relay 245.

It is therefore apparent, that any attempt to initiate a call with no coin or an undervalue coin such as a nickel is frustrated upon complec tion of the first digit. dialled.

Po station Zocoi call. properdeposit Assuming now that the caller is again. at pay station B and wishes to make a local call. Having removed the handset or receiver from. the hookswitch, the same loop circuit is closed and the finder operates to find the. line extending the calling loop thru the paystation trunk to the selector as traced in the preceding section. Upon hearing dial tone as described in the preceding section, assume further that the caller deposits the proper tariff, namely a dime. The dime, or for that matter, a quarter, operates coin spring 23 which closes contact 21 and mechanically locks beneath latch 28. In so doing, the coin disposal magnet I00 in series-with neon tube 30 is connected from ground on spring 26 through dial contact 9 to the -L line. The same switch train seizure sequence as before recited having taken place responsive to raising of the hookswitch, the caller now dials the first digit of his number as before. Just after the last pulse of the digit is sent, dial spring 19 is acted upon by cam [3 in a manner pointed out in reference to Patent No. 2,366,647 and in so doing momentarily closes contact 8 sending a ground pulse originate ing from the ground on coin spring 26 thru contact 8 and out over the -L line. This ground pulse unbalances the energized but unoperated differential relays 260 and 310 causing them to operate. Relay 3| 0 in operating momentarily at this time has no effect as the selector has not stepped to the toll level, viz the tenth level. The efiect of relay am will. be fully des ribed herein-- after in the toll all. Diiierential r lay 250 in operating closes a circuit at contact 26I to relay 280, the circuit being traced from ground on the C lead at closed contact 33! thru contacts 26.1. 233. winding of relay 230 to battery. Relay 280. operating, closes contact 283 and locks to the round on the 0 lead- Contact 28! is also closed by relay 280 shunting out the difierential relay 260. This shunting is done to avoid. transmission loss. Even though the ground pulse which operates relay 26%) is sent after the impulses of the first digit are transmitted, there is more than ample time for relay 280 to operate before relay 300 can operate to cause 290 to operate.

A call may now be extended to subscriber C, The selector operates as hereinbefore described and selects an idle connector in the desired level. The operation of relay 300, causing the calling paystation to be extended through the selector, will not result in the energization of rejectreloy' 290 (contact 284 now being open), as in the case of a call attempted with a nickel. The selector will, of course, not be released and will permit subsequent dialling by the calling subscriber to access the connector shown in the lower left hand corner of Figure 4. The call may thus be completed to subscriber C in a well known manner. Relay 280 in operating before relay 3B0, prevents relay 298 from energizing by opening its energizing circuit at contact 284. The called party answering causes a battery reversal in the connector in well known manner which reverses the field of the right hand winding of shunt field relay'2l0 which is in series with the +1. line. The opposing magnetic fields cause the armature to be attracted. In so operating a circuit is closed to relay 239 thru contact 21 l, the circuit being traced from interrupted ground on Pulse I lead thru contacts 203, 2| l 223, winding of relay 200 to battery. Relay 206 in operating closes contact 202 and opens 203 locking itself thru contacts 223, 2| l, 262 and 214 to ground on the C lead. Pulse 2, timed to come after Pulse i, then operates relay 22!] thru contact 28!. In operating, relay 220 closes contact 224 locking its lower winding therethru to the C lead also. In so operating, relay 22D opens the holding circuit to relay 208 at contact 223. Relay 2&3 releases when ground is removed from Pulse 2 and opens contact before another pulse from Pulse 2 lead can keep it operated any longer. Relay 220 in operating closes ground thru contact 22$ to battery on relay 250, whereupon relay 250 operates. Relay 259 operating closes contact 253, locking itself thru contact 243 to ground. The conversation continues with these relays operated.

Relay 220 in closing contact 225 shorts the right hand winding of shunt field relay 2 [B thereby removing its resistance from line +1.. for improved transmission.

When the conversation has terminated, the calling party in hanging up breaks the loop releasing the switch train as before described, only now relay 250 is operated and has contact 252 closed so that when relay 23B falls back, while relay 24B is yet operated on its sleeve stored residual magnetism, and disposal relay 245 operates as described in the preceding call, +110 volt collect potential is sent out over the L line to fire tube and operate disposal magnets Hill by completing its circuit thru dial contact 9 to ground on coin spring 26. As the coin is collected in well known manner, latch 28 is released and spring 28 restores. The paystation is ready for another call.

' If the call just described is not answered, the caller in hanging up releases the switch train as before, but as relay 250 is not operated because there was never any battery reversal to begin the chain to accomplish this end, when disposal relay 245 momentarily operates, -1l0 volt refund potential is sent over the -L line refunding the dime in the same manner as for the nickel described in the preceding section.

Likewise, certain stations to which calls are to be made free, as perhaps fire, police or the 10- cal telephone ofiice, are arranged so that no battery reversal occurs when the called station answers and therefore, when the conversation is completed and the caller hangs up, the same refunding sequence occurs as described immediately above for an unanswered call to a regular local station.

Pcystation toll call Assume now for the purposes of this illustration that the caller is at paystation B and wishes to make a toll call to some distant point. 01? course, if after raising the hookswitch and hearing dial tone the caller does not deposit a coin of sufficient value, the same sequence of operation as described in the first call will occur after the last pulse of his first digit is dialled. Therefore assume further, that the proper amount, a dime or quarter has been deposited and coin spring 26 has closed ground therethru to connect the disposal magnets 00 to the L line thru dial contact 9 and neon tube 30.

To make a toll call, the digit 0 is prescribed to obtain connection with the toll operator. The same series of relays are energized responsive to line seizure as described previously. Pulsing of the digit 0 pulses the line relay 320 in the selector ten times to raise the wipers ten vertical steps. The selector finding an idle toll operators (CLR) trunk, switches through as previously described and connects it by its wipers to the preceding switch train. The loop is extended thru the selector by relay 300 at closed contacts 3MB and 30213 and extends over conductors 4M and 413 and wipers thru contacts 40! and 404, 406 and 408, 422 and 424, repeating coil windings 441 and 448, upper and lower windings of differential relay 480 and relay 490 to battery and ground respectively.

Relay 490 operates and in closing contact 491 causes relay 460 to operate over the following path: ground, contacts 49L 444, winding of relay 460 to battery. Relay 460 in operating and closing contact 464 causes relay 455 to operate over an obvious circuit. Relay 460 by closing contact 46! applies Ring Back Tone to the -L line. Relay 460 in closing contact 463 grounds the C lead through the lower winding of relay 456 to hold the switches. Relay 490 in closing contact 494 prepares a circuit to the operator's lamp 495. The ground pulse as sent from the dial, unbalances and operates differential relay 3) in the selector, closing contact 3!! which in conjunction with the closing of normal post spring contact 342 which occurs on the tenth or toll level, a circuit is closed to operate relay 350 before the switching relay 3B0 switched the talking lines thru. This circuit is traced from ground at contact 333 thru contacts 301, 3 H and normal post contact 342, winding of slow to release relay 350 to battery. Relay 353 in operating closes contact 353 to lock to its operating ground and closes contact 354 so that when the switch thru relay 300 operates extending the loop just described, contact 308 will place a ground on the -L line (conductor 414). Relay 300, operating when an idle trunk is found, opens the operating circuit to relay 350 at contact 301 but it being slow to release holds up long enough to momentarily place ground on the -L line after it has been extended thru to relays 480 and 490. This ground unbalances and operates differential relay 480 in the CLR trunk. In operating, 480 closes a circuit to operate relay 470 thru contact 48!, the circuit for which is traced from ground on the C lead (conductor 4i2) thru contact 48l, winding of relay 410 to battery. Relay 4'") in operating locks to the C lead ground thru contact 47]. This lock up is necessary until the end of the call so that the operator is able to check for station identification.- As relay 490 and 410 are both operated, a circuit is closed from ground thru contacts 49!, 413 and 426 thru winding of sleeved slow to release relay 4| 5 to battery, operating relay 5. Signal relay 410 also causes contact 414 to close operating the operators call lamp 495 from interrupted generator (Int. Gen.) thru contacts 414, 446 and 494 to flash her call lamp over her call signal (CS) lead. A tone was also put on the C lead at contact 23! when relay 239 in the primary control trunk was operated. This tone additionally informs the operator that the call is from a paystation.

The operator plugs in her cord circuit in well known manner to answer and in so doing grounds the lead H to operate relay 440. Relay 440 operating closes ground at contact 445 to energize relay 430 directly. Relay 430 locks to ground at contact 493 closed by relay 490 and thru contact 435. Relay 430 closes ground thru contact 434 to relay 420 which energizes and also opens contact 43| to remove ring back tone.

Paystation identifying tone reaches the operator over the following circuit: contacts 23, 304, 305, Normal Post Contact 314, conductor M2, wiper and C contact, contact 433 and through the lower winding of coil 450. By transformer action this paystation identifying tone is impressed across the top winding of coil 450 and thence to the operators T and R leads over contacts I and 456. Relay 420 in operating closes contacts 42! and 423 and opens 422 and 424 effecting a battery reversal on the line from battery and ground on relay 490. Relays 430 and 455 restore when their operating circuits are opened at contact 444 and 464 respectively. The ground on the 0 lead to hold the preceding train after relay 460 releases is supplied from the ground on lower winding of relay 450 and thru contact 433 closed by relay 430.

Negative 110 volt refund battery is closed at contact 425 by relay 420 and may be traced from -llll volt source and lamp 421 thru contacts 425, M6 to ground thru winding of high resistance relay 0. Relay 4| 0 in operating closes ground thru contact 4 to operate relay 405. Relay 405 operates to close contacts 401 and 409 which permits the -110 volt refund potential to go out over both lines and automatically refund the initial coin deposited. This refund potential is applied only during the time it takes sleeved slow to release relay M to restore due to the opening of its operating circuit at contact 426 by relay 420. It will also be noted here that relay 410 has contact 412 closed so that the operator may manually control collector refund over lead CO in well known manner from her operators position source of booster potential not shown. Relay 260 being shunted at this time cannot operate from this coin current. The operator may now determine of the caller where the call is to be made to put it thru and access the charges in well known manner. When the calling party answers she may manually collect over lead CC as explained before or in the event that she should forget, when the conversation is over and the calling party hangs up, automatic collection in the control trunk takes place as described in the local paystation call hereinbefore.

If the operator should like to rering the caller for any reason, such as an overtime charge, she applies battery and ground over her tip and ring lines (T and R) in well known manner to energize relay 400. This closes contacts 402 and 403 to put ringing current from GEN out over the loop and thru ringer 2| and back to ground at contact 403.

Local call from a regular Zine Assume now that subscriber A wishes to call subscriber C. The primary control trunk is so arranged that it serves both paystations and regular lines. The EC leads of the finder bank contacts corresponding to regular lines are not grounded as were those of the paystations. When the calling party raises the switchhook at substation A for example, a line loop circuit is closed similar to that described for the paystation calls. The finder starts and seizes the line. As there is no ground on lead EC relay 210 does not energize and this prevents all the other relays in the paystation control trunk from operating. The loop is extended thru the paystation trunk talking conductors to the line relay of the selector.

' Hearing dial tone the party may dial. No ground Toll call from a regular subscriber As this call is made from a regular subscriber, again as in the local call just described from a regular subscriber, the paystation control trunk is bypassed as no ground is forthcoming from the EC lead finder bank contact. The selector extends the loop to battery and ground on relay 490 in the CLR trunk responsive to dialling digit "0 as described in the paystation toll call. However, no ground pulse is forthcoming at the end of the digit since the regular line is not equipped with the special dial. Therefore, relay 480 is not operated which does not permit relays 410 and 4| 5 to operate. Relay 490 in closing contact 494 closes steady ground from contact 415 thru contact 446 to light operators call lamp 495 informing her that the caller is a regular line and not a paystation. Relays 460 and 455 operate as described in the paystation toll call and relay 460 applies ring back tone from the tone generator thru contacts 4H and 43! back over the line. Relay 460 also closes contact 463 to apply ground thru the winding of coil 450 into the 0 lead (conductor M2) to hold the preceding switches.

The operator in plugging in to answer the call in well known manner grounds lead H operating relays 440, 430 and 420 as described in the paystation call, removes ring back tone, reverses battery to the line, attempts to apply the tone identification to the operators set which in this case will be unsuccessful as the call is from a regular line. and allows relays 4'60 and 455 to restore, as described hereinbefore. As relay M5. is not operated, collect battery is not applied to the line since contact M6 is open. The operator now asks for the toll call data and sets up and extends the call in equally well known manner.

What is claimed is:

1. In an automatic telephone system, a pay- 1 spreader 1 1; firstrdi'gittis diallediforztransmitting said marking- 1 potential, and said relay operated in receiptyof said marking potential, for nullifying said ineffectiveness in case a coin-of a certain predeterminedvalue hasv been deposited. 5

2. In an automatic telephonesystem, a paystae tion including a calling device, a hookswitch and. coiir receiving means, a finder having: a paystas. tion trunk and selector associated therewith, means associated with" said paystation' and op erated by said hookswitch when a call is initiated from' said paystationfor: initiating theoperation of said finder to find-and seize said calling 'paystation, a relay associated with said trunk, means foroperating said relay, means included in said calling'device operable immediately subsequent to the termination of only the first digit dialledon said" callingdevice for operating. said last means topperate said-relay, and means operated by the operation of said relay for: determining that a coin of theproper value has been deposited in saidooin receivin means and' that the call is to subsequently" beswitched to completion;

3? In arr-automatic'telephone system, a-paystait tion-including a: calling device," acoin-disposal magnet and receiving mechanism for coins of various: denominations, a first spring in said mechanism operable by deposited-coinsof initially acceptable denominations,another: springin said mechanisntoperablebydeposited.coins ofrinitially unacceptable denominations, means includinga relay-normallyoperable when the dialling of only the firstdigit on-said calling deviceis completed and: said-other-springisoperated, means operated bysaid relay -forpreventing a call from being 09 furtherextendedjmeans' also operated by said relay for'causin'gsaidcoin'magnet to refund coins initially unacceptable;a'marlring potential, means included" in said calling device and operated I thereby-immediately;after the first" digit dialled is* completed for transmittingsaid marking potential "only-whensaid-first coin spring has been operated-;-ja-nother'- relayoperatedin receipt of saidmarking' potential; and means operated by said otherrelay for nullifying said'first'relays ef- 515 feet? 4% In'anautomatic teleplronesystem, a paysta tion*-includi-ng a coin disposal magnet,- a calling" device and coin receiving' mean's for coins of various-denominations; a-selector-accessible to 59 said paystation; means for seizingsaid selector when a callisdnitiatedbysaid-paystation; a" coin spring *in" said receiving; means operatedby deposited coins of initially acceptable denominations, another coin spring operable by deposited coins ofinitially unacceptabledenominations; a marking potentiali means*includedinisaidcalling' device and-operated after only the first digit dialled is completed and only-When saidfirstcoin' spring has been operated" for transmittingrsaid" c marking-potential, a 'relay'operatedup'onreceipt of said"marking-potential, means operated by' said relay for permitting said-selector-to further extend said call, another relay, means for operating: said" other relay only when said" other coinc5 spring -is operated, meansopera-ted by saidother relay wlientoperated"forpreventing'the call f'rombeing further extended, and-"means also-operated by said other relay for operating said magnet to" refund any: initially unacceptable deposited coins.

5; In anautomatic telephonesystem as claimed in claim 4, the operating ofsaid disposal magnetrestoring said coin springs to normal.

6-; In anrautomatic :telephonesystemras claimedt inclaim 4', said marking potentialssentpbeing as ground pulseand said other. relaybeing adifierene tial relay.

7. In an automaticctelephone system asfllaimed'i' in claim 4, said initially acceptable denominations; of coins being dimes and quarters andsaid-initiala ly unacceptable coins beingnickels.

8. In an'automatictelephone system,a paystae tion having coin receiving means; a regular. sub.- scriber station, a finder having a paystation: trunk-.1 and selector. associated therewith and. accessible to said stationsmeans operated by a'eallingrpaye station for operatingv said finder to find" and seize: said calling paystationand connect: said trunk;v and selector ,thereto,.calling: devices at said stations, toll levels in: said selectorcorrespondingrtoe a predetermined first digit dialled a marking p01- tential, means included in said calling device at; only said paystation and operated by said calling; device for sending and marking potentialtosaid selector immediatelyfollow-ing-a first digit dialled-,1 only when a coin of a certain predetermined'valuee has been deposited, a-relayin said selector opera able in receipt of said. marking potential amt means operated by:- said relay, in:casel-said-;:first.: digit dialled, at said rpaystation was-atollv digit, for.permittingsaidselector toseizea toll trunkw 9. In an, automatic telephone system, a P55781331!" tion havinga callingv devic-e, a-.regular subscribers station, ,a finder havingapaystation,trunkiand' selector associated therewith, andaccessible too said stations, means operated by a calling station for operating said finder torfindl andv seize said;

callin staticnand connect said trunk. and selector therewith, a starting relay in' said paystation'. trunk, a first marking potential, said first marking. potential being present only inpcase said' calling; station is a paystation, said starting relaygopem ated by; said marking potential when said finder finds said calling paystation, a seconcljmarkingv potential, means in said" paystation callingd'evice' and operated immediately thereby after compile tion of th'e fii'st dialleddigit for transmitting'saidl second marking potentialtosaidpaystationtrunlt; only when a coin of a predetermined "value .has' been deposited, a secondrelayirr-said paystation'fi trunk" and operated uponreceipt of saidisecondi marking potential, said-operation of saidsecond relay thereby determining that-"a proper" value": coin has-been deposited, meansop'eratedbythe operation of-said second-relay for permitting the" furtherextensionof" the call, andime'ans for" completin a connection through 1 said" paystation trunk-from said regular subscriber station toisai'd" selector bypassing said relays in said control trunk.

GLARENCE IL-O'MAXS Referenccsscited inthe i are of" this *patent- UNITED STATES? PATENTS Number Name 1 Dates;

1,200,788- Williams; Oct:; 10, -;,19-l,6- 1,792,452. Tharp ettal. Feb. 1031931;v 1,855,724- Nelson-l Ap r:z26, .1932-.-. 1,859,885; Paine .May 24119324 1,924,095. Griflins, A-ug; 29,;1933: 2,204,083 Hoyt June 11, 19.401" 2,226,731: Lomax Dec;; 31,. .1940 2,509,477 Carson May. 30;,1950- 2,642,496. Dewar June :16; 1 953 

